#define _CRT_SECURE_NO_WARNINGS 1 	
#include<stdio.h>
int main()
{
	int n = 0;
	int a[10] = { 0 };
	double sum = 0,m=0;
	for (n = 0; n < 10; n++)
	{
		scanf("%d", &a[n]);
		sum += a[n];
	}
	m = sum / 10;
	printf("%lf", m);
	return 0;
}

